When I do the typical upgrade process (Copy files into the directory) for 1.8.1.2 everything copies fine and all permissions are good. When I go to the admin page (or any page) it is completely blank. No errors displayed just a white screen. Any ideas?I have upgraded from 1.6 to 1.7 just fine along with all the 1.7.... updates. but going from 1.7 to 1.8 has not worked.Thank you in advance